Bonneville America Forums Forums Technical Forums General Tech Momentary fuel starvation - what why how?

So I'm riding in the rain this morning and all of a sudden I feel that sputtering like when you run out of fuel. Quickly switched to reserve automatically and looked at my odo - only 30-and-change miles... WTF? Sputtering doesn't quit, in fact starts to die quicker every time I give it throttle - pull off to the side of the highway real quick as it dies. Let it sit a second and hit the ignition - thinking water made a short somewhere but it cranked right up - still sounding horribly fuel-starved. Open the gas cap and peek in just in case...yup sure enough it's full, but here's the weird part. As soon as I take off the gas cap, the sputtering quits and the engine revs back up to purring normally.

WTF???

Sounds very much like a blocked fuel vent.(rubber hose coming down from under tank towards front.) check for kinks or sh#t on the open end.

This is symptomatic of the common fuel vent hose problem: kinked hose if you've recently had the tank off, blocked lower end from road debris if you've been riding wet, or an over-full tank. A while back member Singring posted a great workaround: carry a small section of clear tubing that fits snugly over the vent tube in the filler opening, attach and blow to clear tube. Cracking the cap until you run some fuel thru is the easiest...and runninng fuel thru is the most fun.

Can't remember who thunked this one up but a great idea nonetheless:

Cut the bottom end of the tube at a 45 degree angle, with that cut facing to the rear. This allows for more surface area on the hole and a less likely ability to clog with water.

Apparently it's the water clogging that vent tube...never had a problem doing that before and suddenly the days it rains it does it at random intervals - did it to me twice coming home in cats and dogs tonight. Spun the cap partway open and back down tight, problem stops.

Thanks for the input all, I'll give that last a try.

Rex

Had that happen to me couple years ago on my way back home from Chehalis, it was dumping hard (needed scuba gear) and had to pull over a couple of times and losen the cap for a second or so.

Soren